In certain situations, network communication is more efficient through use of broadcast or multicast technology. Broadcast data is data that is sent once and received by all members on a given network. For example, all nodes coupled to a network will receive the same broadcast transmission. Multicast data is data that is sent once on a network to a given multicast channel and received by all clients registered to receive data on the given channel. For example, all computer systems coupled to a network can receive the same multicast data if they are listening on the given multicast channel.
However, when broadcasts or multicasts require a response from the recipients, the network can become overwhelmed by the responses. For example, if a multicast to 100 recipients causes the recipients to download a file from a Web server, the Web server my crash as a result of too may requests. If routers or switches within the network are overwhelmed by the responses, the routers and/or switches may drop packets in which case the requested responses never reach the broadcasting/multicasting device.
One solution is to send an exclusion list along with the data that requests a response from the broadcast/multicast recipients. An exclusion list is a list of devices that should not reply to a broadcast or multicast message. However, as the exclusion list becomes large, multiple packets may be required to broadcast/multicast the exclusion list. If a target device does not receive one or more of the packets carrying the exclusion list, the device may respond even though it should have been excluded. Another shortcoming of broadcasting/multicasting the exclusion list in multiple packets is that coordination and management of the exclusion list is complex.